Production of printing forms



Aug. 4, 1942. F. ALBERS ETAL 2,291,673

PRODUCTION OF PRINTING FORMS Filed Aug. 15!, 1939 soft coating of res/Lnor the dzlke hardenoabde cololid dag er of bne or me like bag ta, M g erkwquer paper base Zacquew F10; tz Adi Jews Eduard Schaemwnn INVENTORS THEl R ATTORNEYS Patented Aug. 4, 1942 PRODUCTION OF PRINTING FORM FritzAlbers and Eduard Schloemann, Leverkusen-Wiesdorf, Germany, assignors,by mesne assignments, to General Aniline & Film Corporation, New York,N. Y., a corporation of Delaware Application August 2, 1939, Serial No.287,858

Claims.

Our present invention relates to the producglogn of printing forms,particularly for flat print- A known process for producing forms forflat printing consists in writing by hand or by typewriter on a colloidlayer capable of being hardened with a hardening ink. The layer is.thenrolled with a fatty color which adheres only to the hardened parts. Thescript is then transferred by pressure to paper or the like.Alternatively, the colloid layer may be sensitized with bichromate andprinted with a pattern by first expo in the layer to light through acopy. whereby the gelatin is hardened only at those parts which havebeen illuminated. The printing is performed as described above, namelyby rolling the surface with a printing color which adheres only to thehardened parts. The process has the disadvantage that after the patternor script has been applied corrections of the script on the printinglayer cannot be made without damaging the surface of the printingmaterial.

Our invention has for one object to avoid this disadvantage by providinga colloid layer capable of being hardened with a coating i-mpermeable toa hardening bath.

Another object of our invention is to provide a. colloid layer capableof being hardened and having a coating of such a degree of softness thatby a locally limited pressure the underneath colloid layer is exposed.After application of the pattern the colloid layer is hardened in knownmanner and the coating removed.

A further object of this invention is the provision of a colloid layerwhich contains for the purpose of obtaining a better adhesion of theprinting color to the said colloid layer a substance which imparts toits surface a certain porosity and roughness. For this purposesilicates, for instance kieselguhr, are especially suitable.

Other objects of our invention will appear more in detail from thefollowing description.

The colloid layer may be given sufficient mechanical strength for theprinting by supporting it on a carrier which may be of paper or ofsheets of known artificial materials, such as Celluloid, Cellophane(registered trade-mark), acetyl cellulose, polymerized vinylchloride,polymerized styrene or the like. When paper is used it is preferable tocoat it on both sides with Germany August 12, 1938 colloid layer may besupespecially high the sheet (for instance, aluminported on a'metal iumsheet) which, the colloid layer, may be roughened or provided with anintermediate sticky layer. Between the metal and the colloid layer theremay be a layer g pattern has been applied. The coating may cona lacquermade from cellulose derivative'or the like in order to make it stable inthe hardening bath. When the mechanical requirements are 5 sist ofnatural or artificial resins, cellulose derivatives or the like, ofsufficient degree of softness. If necessary the degree of softness maybe procured by the addition of the necessary proportion of a softeningagent (for instance, tricresyl phosphate, natural or artificial waxes).The coating is to be so soft that by a locally limited pressure, forinstance by the blow ofa typing lever, the coating is pressed aside andthe underlying colloid layer is exposed. By manuscript or typescript ordrawing on the coating layer which may first be covered with a thinsheet of paper, the colloid layer becomes visible as the script ordrawing and these parts can be hardened in known manner by bathing thelayer in a hardenin solution. After removing the coating layer by meansof a bath of a solvent for the coating or in any other manner, such asby peeling, scratching or the like, and then moistening and rolling witha fatty color, the printing form thus made can be used for printing. Acorrectly orientated reproduction is obtained by performing the printingin a similar manner as used offset printing.

A section of one modification of a printing form in accordance with thepresent invention is illustrated in the annexed self-explanatorydrawing. It is not intended, however, that the scope of applicantsinvention is to be limited to the modification shown.

The process has the special advantage that after the script or drawingor the like has been produced on the surface it is easy to makecorrections by again applying the coating where the mistakes are andrepeating the writing or drawing.

Theprocess is suitable when modified in obvious manner for producinghigh relief and basrelief printing forms. In this case the colloid forthe better adhesion of is hardened throughout at the ing with the scriptor drawing.

The following examples illustrate the invention.

Example 1 On the baryta layer of a barytized paper lacquered on bothsides there is applied first a gelatin layer and on this the followingsolution:

parts correspond- Victoria Blue 133 (see Schultz, Farbstofltabellen, 7thedition, 1st volume, No. 822) 1 After evaporating the solvent thereremains on the gelatin layer a soft coating impermeable to water, uponwhich one can write so as to uncover the underlying gelatin layer. Thepaper is then bathed for a few minutes in a solution of. a chromium orzirconium salt capable of hardening the gelatin. The excess of thissolution is removed by washing in flowing water and then the coatingimpermeable to water is washed away by a mixture of alcohol and ether(2:1). After moistening the printing surface with water containinglycerin a fatty color is applied by a roller and printing follows in.the usual manner. Instead of using hardening baths one can alsosensitize the printing layer. It suflices in this case to expose theprinting material to daylight. Since the colored coating light, thegelatin is hardened only at those parts where the coating is pressedaside.

Example 2 On the baryta layer of a barytized paper lacquered on bothsides there is applied a gelatin layer containing kieselguhr. On thislayer there is cast the following solution:

Polymerlzed styrene grams Carbon tetrachloride -cubic centimeters 8,877Mineral oil as the softening agent -do 710 Sudan Blue G (see Schultz,Farbstoiftabellen, 7th edition, 2nd supplementary volume, page 261)grams 13 After evaporating the carbon tetrachloride there remains on thecolloid layer a soft coating bluecolored and impermeable to water. Onthe printing material thus obtained one writes by typewriter. Theprinting material is then treated in a hardening bath. The coating issubsequently removed by bathing in carbon tetrachloride and the printingform is then rolled with a fatty color. Printing follows in the usualmanner, for instance by an onset printing machine.

Example 3 On the baryta layer of a paper barytized and lacquered on bothsides there is applied first a gelatin layer and on this the followingsolution:

is impermeable to the I .in the usual manner.

Example 4 On the baryta layer of a barytized paper lacquered on bothsides there layer containing kieselguhr. On this layer there is cast thefollowing mixture:

60 grams of collodion cotton carrying its own weight of spirit, 110grams of higher aliphatic alcohols of 10-14 C-atoms or mixtures thereof,'70 grams of xylenylglycol, 15 grams of chlorinated diphenyls, 15 gramsof butanol, 50 grams of the solvent consisting of methanol and esters oflower fatty acids, 20 grams of butyl acetate, grams of methylenechloride, 880 grams of denatured ethyl alcohol, 440 grams of ethylether. I gram of Victoria Blue or another dyestuff soluble in alcohol.

After evaporating the solvents there remains on the gelatin layer a softcoating impermeable to water, upon which one writes so as to uncover theunderlying layer. The paper is then bathed in a solution of hardeningagents and the coating is removed by washing with a solution of alcoholand ether (2:1). After moistening the printing surface with watercontaining glycerin a fatty color is applied by a roller and printingfollows in the usual manner, for instance by an offset printing machine.

We claim:

1. In a process of producing a printing form from a printing materialprovided with a colloid layer, said colloid being capable of beinghardened, the improvement which comprises applying on the surface ofsaid colloid layer a coating impermeable to hardening baths and havingsuch a degree of softness that said colloid layer is exposed by alocally limited pressure on said coating, applying a recording on saidcoating so as to expose said colloid layer at the parts of recording,hardening said colloid layer in a hardening bath, and removing saidcoating by washing 2. In a process of producing a printing form from aprinting material provided with a gelatin layer, the improvement whichcomprises applying on the surface of said gelatin layer a coatingimpermeable to hardening baths and having such a degree of softness thatsaid gelatin layer is expoud by a locally limited pressure on saidcoating, applying a recording on said coating so as to expose saidgelatin layer at the parts of recording, hardening said gelatin layer ina hardening bath, and removing said coating by washing.

3. In a process of producing a printing form from a printing materialprovided with a gelatin layer containing a substance imparting roughnessto the surface thereof, the improvement which comprises applying on thesurface of said gelatin layer a colored coating impermeable to hardeningbaths and having such a degree of softness that said gelatin layer isexposed by a locally limited pressure on said coating, applying arecording on said coating so as to expose said gelatin layer at theparts of recording,

is applied a gelatin hardening said gelatin layer in a hardening bath,and removing said coating by washing.

4. In a process of producing a printing form from a printing materialprovided with a gelatin layer, the improvement which comprises applyingon the surface of said gelatin layer a bluecolored coating comprising amixture of collodion and trlcresyl phosphate and having such a degree ofsoftness that said gelatin layer is exposed by a locally limitedpressure on said coating, applying a recording on said coating so as toexposesaid gelatin layer at the parts of recording, hardening saidgelatin layer in a hardening bath, and removing asid coating by washing.

5. In a process of producing a printing form from a printing materialprovided with a gelatin layer, the improvement which comprises applyingon the surface of said gelatin layer a bluecolored coating comprisingamixture of polymerized styrene and mineral oil and having such a degreeof softness that said gelatin layer is exposed by a locally limitedpressure on said coating, applying a recording on said coating 50 as toexpose said gelatin layer at the parts of recording, hardening saidgelatin layer in a hardening bath, and removing said coating by washing.

6. In a process of producing a printing form from a printing materialprovided with a gelatin layer, the improvement which comprises applyingon the surface of said gelatin layer a blackcolored coating comprising amixture of chlorocaoutchouc, chlorinated diphenyls, stearin pitch, andhigher aliphatic alcohols with 10 to 14 C-atoms, and having such adegree of softness that said gelatin layer is exposed by a locallylimited pressure on said coating, applying a recording on said coatingso as to expose said gelatin layer at the parts of recording, hardeningsaid gelatin layer in a hardening bath, and removing said coating bywashing.

7. A printing material consisting of a support and two superimposedlayers on one side of said support, the layer next to said support beingessentially of a colloid capable of being hardened,

the upper layer being impermeable to hardening baths and having such adegree of softness that said colloid layer is exposed by a locallylimited pressure on said upper layer and selected from the classconsisting of resins and cellulose derivatives.

8. A printing material consisting of a paper layer and two superimposedlayers on one side of said paper layer, the layer next to said paperlayer being essentially of a colloid capable of being hardened, theupper layer being impermeable to hardening baths and having such adegree of softness that said colloid layer is exposed by a locallylimited pressure on said upper layer and selected from the classconsisting of resins and cellulose derivatives.

9. A printing material consisting of a paper layer and two superimposedlayers on one side of said paper layer, the layer next to said paperlayer being essentially of a colloid capable of being hardenedcontaining a substance imparting roughness to the surface thereof, theupper layer being impermeable to hardening baths and having such adegree of softness that said colloid layer isexposed by a locallylimited pressure on said upper layer and selected from the classconsisting of resins and cellulose derivatives.

10. A printing material consisting of a paper layer and two superimposedlayers on one side of said paper layer, the layer next to said paperlayer being essentially of a colloid capable of being hardenedcontaining a substance imparting roughness to the surface thereof, theupper layer being colored and impermeable to hardening baths and havingsuch a degree of softness that said colloid layer is exposed by alocally limited pressure on said upper layer and selected from the classconsisting of resins and cellulose derivatives.

11. A printing material consisting of a paper layer lacquered on bothsides, a layer consisting of a colloid capable of being hardened and asubstance imparting roughness to the surface thereof and fixed on oneside of said paper layer, a colored coating layer coveringsaid colloidlayer and being impermeable to hardening baths and having such a degreeof softness that said colloid layer is exposed by a locally limitedpressure on said coating layer and selected from the class consisting ofresins and cellulose derivatives.

12. A printing material consisting of a metal layer provided on bothsides with a paper coating, a layer consisting of a colloid capable ofbeing hardened and a substance imparting roughness to the surfacethereof and fixed on one side of said metal layer, a colored coatinglayer covering said colloid layer and being impermeable to hardeningbaths and having such a degree of softness that said colloid layer isexposed by a locally limited pressure on said coating layer andselected'from the class consisting of resins and cellulose derivatives.

13. A printing material consisting of a support and two superimposedlayers on one side of said support, the layer next to said support beingessentially of gelatin, the upper layer blue-colored comprising amixture of collodion and trlcresyl phosphate and having such a degree ofsoftness that said gelatin layer is exposed by a locally limitedpressure on said upper layer.

14. A printing material consisting of a support and two superimposedlayers on one side of said support, the layer next to said support beingessentially of gelatin, the upper layer blue-colored comprising amixture of polymerized styrene and ineral oil and having such a degreeof softness that said gelatin layer is exposed by a locally limitedpressure on said upper layer.

15. A printing material consisting of a support and two superimposedlayers on one side of said support, the layer next to said support beingessentially of gelatin, the upper layer black-colored comprising amixture of chlorocaoutchouc,

chlorinated diphenyls, stearin pitch, and higher aliphatic alcohols with10-14 C-atoms or mixtures thereof and having such a degree of softnessthat said gelatin layer is exposed by a locally limited pressure on saidupper layer.

FRITZ ALBERS. EDUARD SCHLOEMANN.

